bnx2x: fixed ethtool statistics for MF modes

Previosuly, in MF modes `ethtool -S' lacked some of the statistics
which appeared in non-MF modes. This has been fixed.

Signed-off-by: Yuval Mintz <yuvalmin@broadcom.com>
Signed-off-by: Eilon Greenstein <eilong@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>